Use simple CompilePolicy in Nullsafe flavour

Summary:
See: https://www.javadoc.io/doc/io.earcam.wrapped/jdk.compiler/latest/com/sun/tools/javac/main/JavaCompiler.CompilePolicy.html

With simple compilation policy javac does same tasks on all files instead of doing all tasks on a one file or group of files. By doing that we make sure that all files will finish analyze task before starting generate one.

Reviewed By: artempyanykh

fbshipit-source-id: 3b3fa2f848a244bbf806e42806aaceadb16644f6

Author: geralt-encore

src/com/facebook/buck/jvm/java/Nullsafe.java

@@ -142,7 +142,7 @@ public static JavacOptions augmentJavacOptions(
     JavacOptions.Builder javacOptionsBuilder =
         JavacOptions.builder(javacOptions)
             .setStandardJavacPluginParams(augmentedPluginParams)
-            .addExtraArguments("-XDcompilePolicy=byfile")
+            .addExtraArguments("-XDcompilePolicy=simple")
             .addAllExtraArguments(nullsafeConfig.getExtraArgs());
 
     if (shouldReportJson(buildTarget)) {